This reports which ATM Adaptation Layer this switched virtual circuit is using to map higher-layer data onto ATM cells -- AAL1 for constant-bit-rate/circuit-emulation traffic, AAL5 for the more common data or LAN-interconnection traffic -- negotiated during SVC call setup rather than statically configured like on a PVC. An admin seeing an SVC unexpectedly using aal1(1) when they expected data traffic would investigate what application actually placed that call, since AAL1 signals circuit-emulation-style usage rather than typical bursty data. For example, an SVC supporting an on-demand voice trunk would show cktSvcAalType as aal1(1), while an SVC used for LAN interconnection would typically show aal5(5).